A subclass to allow splitting Django models into a package without manually specifying app_label for every one.

db.py

from django.db.models import base
from django.conf import settings

class ModelBase(base.ModelBase):
    def __new__(cls, name, bases, attrs):
        parents = [b for b in bases if isinstance(b, ModelBase)]
        if not parents:
            # Don't run our fixup on the model base class itself.
            return super(ModelBase, cls).__new__(cls, name, bases, attrs)
        
        old_module = attrs['__module__']
        for installed_app in settings.INSTALLED_APPS:
            if old_module.startswith(installed_app):
                attrs['__module__'] = installed_app+'.models'
                break
        else:
            raise ValueError('Unable to find appropriate app label for model %r', name)
        
        return super(ModelBase, cls).__new__(cls, name, bases, attrs)


class Model(base.Model):
    __metaclass__ = ModelBase

    class Meta:
        abstract = True